It is difficult for an observer to experience how a patient fitted for a device such as an intraocular lens, contact lens or eyeglass lens actually sees an object.
It is difficult for an observer to actually experience how things can be seen by a patient and various studies have been conducted in order to solve this problem. In one such study, an ocular model which allows even a person of less advanced age to experience visual characteristics, illuminated visual environment, chromatic environment and the like of a person of advanced age has been proposed (Japanese Patent Laid-Open No. 63-129317).
When visual acuity drops due to a cataract or the like, attempts have been made to recover the visual acuity of the patient by the implantation of an intraocular lens (IOL) to replace a crystalline lens whose function has been impaired. Intraocular lenses can be divided generally into mono-focus lenses having one focal point, and multi-focus lenses having a plurality of focal points. Specifically, the multi-focus lenses include double-focus lenses, triple-focus lenses, progressive multi-focus lenses and the like. Further subdivisions are also possible.
A lens suitable for a patient is selected among these various intraocular lenses.
Up until now, however, a doctor has been unable to know in advance how things would actually be seen by a patient after an intraocular lens is implanted. Likewise, the patient in whom the intraocular lens was implanted could not know in advance how things would be seen after the intraocular lens is implanted. That is, both the doctor and the patient could know only numerical data such as diopter of the intraocular lens and could not confirm, for example, properties such as scattering characteristics and contrast in advance.
Furthermore, even if the doctor wanted to check whether the intraocular lens had been implanted in the patient properly, there has until now been no other way but to ask the patient about scattering characteristics, contrast and the like, and to check the results by measuring the visual acuity by means of eyecharts and other tests.
Meanwhile, researchers and developers of intraocular lenses also could not know how things would be seen by a patient when a newly developed intraocular lens is implanted. This fact has been a big obstacle in the research and development of intraocular lenses.
Accordingly, it is an object of the present invention to solve the aforementioned problems by providing a simulation apparatus which allows a retinal image of a object when an intraocular lens is implanted to be simulated.
There has been an increase in patients in recent years who try to recover their visual acuity by wearing contact lenses in place of eye glasses when their visual acuity is lowered. Contact lenses can also be classified into single-focal lenses having one focal point per lens and multi-focal lenses having a plurality of focal points per lens. Furthermore, multi-focal lenses include, for example, bifocal lenses, trifocal lenses, progressive lens and the like, which can be further subclassified.
In the case of contact lenses, it is also required to select a suitable contact lens for a patient among these various lenses.
However, researchers or developers of such contact lenses have, like the developers of intraocular lenses, not been able to know how a patient actually sees an object with a given newly developed or proposed contact lens. This has inhibited the research and development of contact lenses. Lastly, similar problems have been encountered by the developers of eyeglass lenses, and such developers have also sought after an accurate method or apparatus of simulating the retinal image of an individual or patient wearing a particular eyeglass lens.
In view of the above problems, it is a further object of the present invention to provide an ocular optical system simulation apparatus for simulating a retinal image of a patient when a contact lens or eyeglass lens is worn.